In spite of the proven short-term efficacy of cognitive-behavioral and pharmacologic treatments for OCD, remarkably little data are available to guide clinicians in the long-term treatment of the disorder. The vast majority of OCD patients are treated with serotonin reuptake inhibitors (SRIs) that have significant long-term adverse effects. While abrupt discontinuation following short-term SRI treatment leads to relapse in most OCD patients, SRI discontinuation in patients treated longer than 1-2 years has not been systematically examined. It is critical to empirically evaluate whether OCD patients maintained long-term on SRIs can discontinue without symptom exacerbation, to examine potential strategies to increase discontinuation success amongst the range of OCD patients seeking to discontinue, and to identify predictors of discontinuation success. The proposed research project will gather preliminary data on the discontinuation of long-term SRIs in OCD by evaluating the feasibility, acceptability, and preliminary efficacy of a unified, transdiagnostic CT based protocol (UP) in improving both discontinuation success and outcome. 30 OCD patients seeking to discontinue long-term SRIs will be randomized to receive a conservative taper and monitoring protocol, Taper and Monitoring (TAP-M), or TAP-M + UP. This study addresses issues of fundamental clinical significance for which clinicians have no empirical guidance: (1) Can a meaningful proportion of OCD patients wanting to discontinue an SRI after two or more years of treatment do so without significant clinical worsening? (2) Does a unified CBT-approach improve discontinuation outcomes? and (3) Can distress tolerance provide a framework for understanding discontinuation success? This study may prove to be a useful model for SRI discontinuation strategies in other disorders and is a first step towards identifying potential predictors of discontinuation success.